<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<form action="/pay" method="post">

    <p>
        <input id="out_trade_no" name="out_trade_no" type="text" placeholder="订单商户号" value="111">
    </p>

    <p>
        <input name="total_amount" type="text" placeholder="付款金额" value="0.01">
    </p>
    <p>
        <input name="subject" type="text" placeholder="订单名称" value="测试订单">
    </p>
    <p>
        <input name="body" type="text" placeholder="商品描述" value="测试商品">
    </p>


    <input type="submit" value="付款">
</form>
<script>
    var date=new Date();

    document.getElementById("out_trade_no").value=
        date.getFullYear()+""+date.getMonth()+1+""+date.getDate()+""+date.getHours()+""+date.getMinutes()+""+date.getSeconds();
</script>
</body>
</html>